In flotation systems, the fraction to be separated occurs as foam, which in many systems is removed by way of a foam chute. If excess foam is generated, the result can be operational failures due to the difficulties in removing the precipitated or to-be-precipitated foam, or through an overflow of the excess quantity of foam out of the foam chute.
From the German utility patent 87 01 636 it is known to control the amount of air in an injector by means of throttle valves. Associated with this control of the amount of air, naturally, is also the control of the generated foam quantity of the flotation system. However, priority goes here to the type of generated air bubbles, so that here the adaptation of the air is essentially required only to the throughput amount of suspension to be subjected to flotation so as to produce an optimal flotation suspension air mixture. Thus, a specific control of the foam quantity is not possible here.
The flotation device according to the German patent application 29 04 619 employs a circular flotation flow, and the foam is sucked away at the end of this flow by a collection funnel. It is hardly conceivable that large suspension quantities can be managed with this device.
The German patent application 36 35 713 provides for a foam destroyer in connection with the foam chute, where the air is removed from the foam by an eddy flow, which aims to cause the foam to collapse. The disadvantage seems to be that only the energy of the liquid flow must bring about the foam destruction effect. Due to the heavy mixing of the liquid with air, there are certain limits to the effectiveness of this device.
The problem underlying the invention is to propose a process for the control of a flotation system in order to preclude operational failures due to the difficulties in removing the foam quantity.